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Postdural puncture headache linked to increased risk of subdural hematoma



Postdural puncture headache in women who have undergone neuraxial anesthesia in childbirth may be associated with a small but significant increase in the risk of being diagnosed with intracranial subdural hematoma, research findings suggest.

A cohort study, published online in JAMA Neurology, looked at the incidence of intracranial subdural hematoma within 2 months of delivery in 22,130,815 women, using data from the U.S. Agency for Healthcare Research and Quality’s National Readmission Database.

The overall rate of postdural puncture headaches was 309 per 100,000 deliveries, and the overall incidence of subdural hematoma was 1.5 per 100,000 deliveries. Among the women with postdural puncture headache, however, the unadjusted rate of subdural hematoma was 147 per 100,000. After adjusting for confounding factors, women who experienced postdural puncture headache had a nearly 200-fold higher risk of subdural hematoma (odds ratio, 199; P less than .001), representing an absolute risk increase of 130 per 100,000 deliveries.

“This was a small absolute increase because of the rarity of this outcome in this population,” wrote Dr. Albert R. Moore of the Royal Victoria Hospital at McGill University, Montreal, and coauthors. “However, this is an important and devastating outcome for a common exposure in young and usually healthy mothers.”

The authors noted that these findings confirmed other reports linking postdural puncture headache and intracranial subdural hematoma. The proposed mechanism connecting the two conditions was that decreased intracranial pressure from cerebrospinal fluid leakages leads to “sagging” of the brain and tension on the veins between the dura and arachnoid, which in turn could trigger a rupture and formation of a subdural hematoma.

Other risk factors for subdural hematoma included coagulopathy, arteriovenous malformation, and delayed blood patch. The investigators also found that obesity was associated with a lower risk of headache after postdural puncture, which might be the result of increased intracranial pressure providing resistance to the development of subdural hematoma.

There was a significant interaction between postdural puncture headache, severe preeclampsia, and chronic hypertension. In the absence of postdural puncture headache, severe preeclampsia and chronic hypertension were both independently associated with significant increases in the risk of subdural hematoma, Dr. Moore and associates noted.

In women who experienced postdural puncture headache, only chronic hypertension was significantly associated with subdural hematoma, they said.

The study was limited in being observational and at risk of misclassification. In addition, there was a risk of surveillance bias in that women with postdural puncture headaches might be more likely to receive brain imaging that would pick up minor subdural hematomas, the investigators said.

The study was supported by McGill University Health Center’s department of anesthesia. The authors reported no conflicts of interest.

SOURCE: Moore A et al. JAMA Neurol. 2019 Sep 16. doi: 10.1001/jamaneurol.2019.2995.

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